Conventional wood utility poles frequently require a grounding electrode to ground the neutral conductor of overhead power lines. The minimum code requirements for a wood pole grounding is four grounds per mile, and a ground at every equipment location. If the poles are constructed of steel, a ground rod is typically utilized for every pole.
The use of a ground rod to ground a utility pole suffers a number of drawbacks. First, when soil freezes, electrical resistance of the ground rod increases dramatically. In addition, ground rods are difficult to install and remove, and are virtually impossible to install in some soil conditions (such as rocky soil or hardpan).
Connection of the ground rod to the power line requires a clamp connecting a grounding wire from the pole to the rod, the clamp normally being installed one to two feet deep in the ground, in a high corrosion zone of the ground. The ground rod wire is typically attached to the pole above the ground line, where they can be easily cut or damaged.
Conventional steel poles are formed of galvanized steel in an elongated tubular configuration, the steel conventionally less than one-quarter inch thick. Because the National Electric Safety Code (NESC) requires any grounding device to be formed of material one-quarter inch thick or greater, the lower end of the pole itself cannot be used to electrically ground the pole. Thus, an additional grounding apparatus is necessary to electrically ground power lines supported by a steel utility pole.
Bearing plates for tubular steel utility poles are typically necessary to support the pole in the ground. The open tubular end of the pole does not provide a sufficient bearing surface to support the pole. Conventional bearing plates are rectangular in configuration, and attached to the bottom of the pole to provide the required bearing surface for the pole. However, because the conventional rectangular bearing plate projects beyond the diameter of the pole, the pole is not easily turned once positioned in a hole, nor is the pole easy to remove from the ground, once installed.